Drive for air compressors



April 13, 1948.

H. J. FINDLEY DRIVE FOR AIR COMPRESSORS Filed Aug. 24, 1944 INVENTOR. gown/e0 J HNDLEY 4 7- 7'0ENEY5 fiathted Apr. 13, 1948 OFFICE naive non AIR coMrREssoRs Howard J. Findley, Ohardon, Ohio, assignor to Eaton Manufacturing Ohio, a corporation of Ohio ApplicationAugust 24, 1944, Serial No. 550,961 g This invention relates to air compressors and. more particularly to an improved drive for air compressors being used as auxiliary equipment on motor vehicles.

Air compressors are frequently provided on motor vehicles as a source of air pressure for operating brakes and for other auxiliary purposes. Where such compressors have been operated from the driving motor of the vehicle they have heretofore been subject to considerable abuse and to rapid wear by reason of the fact that the vehicle driving motor is a variable speed motor and at times is operated at a very high R. P. M. resulting in an excessive speed for the compressor.

This condition is especially troublesome in the case of trucks and busses which frequently shift into low gear and the corresponding higher motor speeds result in the compressor being driven at an excessive speed during a considerable portion of the time. The operation of the compressors at such excessive speeds causes excessive Wear requiring frequent repair or replacement and also dissipates a substantial percentage of the horsepower developed by the vehicle motor.-

The present invention overcomes thisproblem by providing an improved drive for an air compressor in which a substantially constant speed coupling is employed in driving the compressor from a variable speed vehicledriving motor.

Another object of this invention is to provide an improved drive for an air compressor in which the coupling is a substantially constant speed magnetic coupling.

The invention also rovides an improved drive of this character, in which a switch controlling the magnetic coupling is actuated in response to variations in the pressure of the air delivered by the compressor. 4

Still another object of this invention is to provide improved brake actuatingmechanism for air-operated brakes of a motor vehicle, in which a constant speed magnetic coupling is employed for driving an air compressor from the vehicle motor and the efiectiveness of such coupling is controlled in response to pressure variations in the air delivered by the compressor.

Other objects and advantages of the invention will be apparent from the following description when taken in conjunction with the accompanying sheet of drawings wherein Fig. 1 is a side elevation showing a motor vehicle to which the present invention has been'applied.

Fig. 2 is an elevational view showing the vehicle motor and the improved driving-means for operating the air compressor therefrom; and

Fig. 3 is a diagrammatic view, partly in section, showing the substantially constant speed magnetic coupling and the pressure responsive control means.

2 Claims. (erase -15) Company, Cleveland,

Proceeding with a more detailed description of the invention, there is shown in Fig. 1 a motor vehicle l0 having wheels ll provided with brakes l2 which are actuated or controlled by air under pressure supplied thereto through conduits It. The vehicle I!) is also provided with cab or body [4 containing a drivers compartment 15 and with a hood l6 containing a motor compartment H. A variable speed internal combustion motor 18 is located in the compartment l1 and is connected with the wheels I l in a conventional manner for propelling the vehicle. The motor 18 is controlled from the driving compartment I5 and operates at speeds which may vary from an idling speed of approximately 500 R. P M, to a maximum operating speed of approximately 3500 R. P. M. Associated with the vehicle motor it are the usual radiator I9 and cooling fan 20. The vehicle motor 18 can be a conventional internal combustion engine of either the reciprocating or rotary type or can be an internal combustion turbine.

For supplying the compressed air for actuating or controlling the wheel brakes l2, or for other auxiliary purposes, the motor vehicle I0 is equipped with an air compressor 22 which is mounted on or adjacent the vehicle driving motor [8. The compressor 22 includes a rotary drive shaft 23 which extends adjacent to an auxiliary power takeoff means 24, of the vehicle motor l8 and which, in this instance, is in the form of a driven shaft 24a having pulleys 25 and 26 thereon. The air compressor 22 also includes an air delivery means or conduit 21 which is connected with a storage tank 28.

The flow of air to the wheel brakes l2 ofthc vehicle [0 is controlled by a suitable control valve 30 which may be located adjacent the drivers compartment 15 and. with which the conduits l3 are connected. Air from the tank 28, or from the compressor 22 directly in the event that the tank 28 is omitted, is supplied to the control valve 30 through the conduit 3|. The valve 3|] is adapted to be manually actuated for causing the application or release of the wheel brakes I2, as by means of a brake pedal 32 located in the drivers compartment.

The air compressor 22 is connected with the auxiliary power take-off means 24 by suitable torque-transmitting means which, in this instance, utilizes a belt 34 extending around the pulley 25. An important feature of the present invention is the use of a substantially constant speed coupling 35 in the torque-transmitting means which connects the compressor 22 with the power take-off 24. This constant speed coupling is preferably in the form of an eddy-current device or magnetic coupling which is operable with slippage as will be further explained hereinafter. In this instance the coupling 35 is mounted on 40 thereof is ldeeener ized hy the on winding At!- of thegmagnetic; couplin \is .driven r Continuously -.from ,the ,PQWQ ztake o .fIfhe air'cornpressor ,2; thus is. drl enla. t vvvhich is substantially. constant ifo-r all neratins tank zagreaches a Qpredeterminedya e ittwill 3 the compressor shaft 23 and is provided with a pulley 36 around which the belt 34 extends.

A magnetic coupling suitable for gthe'purpose-of the present invention is ffurther illustrated liniFig. 3 of the drawing and comprises a housing 31 formed of magnetic material and rotatably mounted on the compressor shaft 2.3 ,bymearnsoi suitable bearings 38. The magnetic coupling also includes a rotor 39 constructed aefsmagnntic ma: terial and carryingan energizingmoil or -winding M]. The rotor 39 is located in the housing 31 and is connected with the shaft ii -as by means of the pin 4 l. The winding 40 is adapted to be ener- ,which enables suchcompressor to be driven at .a substantially constant speed and prevents such compressor from being operated at excessive finqedfirzwl i h usualgly result in rapid wear and ca llyifailuite. ift will be seen also that the present invention provides a novel pressure responsive rcontrol fora substantially constant speed magnetic coupling through which the air compressor gized by a suitable electric circuit whichiincludes.

slip rings 42 and 43 mounted on the shaft 23 in insulated relation :and :connected with rtheieners n Winding, nds-ha r." ii ehe fle e 45 cooperating .with'such slip-rings.

The energizing circuit for .the magneticccqupling 35 isconnectedwithga suitable so j current, :such as the storage ,battery ifilil of the :motorvehicle, andincludes akeyf-operated switch 43 which .may be the ignition switch {the rye hicle. The 'energi-zing'circuit .for th, coupling also 'includes a pressure {responsive switch 49 having pairs ;of cooperating [movable and stationary :contactsfifi andvil. movable contacts :50 are connected n or l-ca member 52 which is adaptedto be eactu a pressure responsive fiylphon or diaphragm device 54, the latter being :connecte. li the air storage tank zlby a-;conduit .55,

The magnetic; coupling 35 1s operable with slippage, as mentionedeabove and When-t either-oflthe switches-A3 engine housin b ber 31 will be rotated idly about the rotor. 39' and the compressor 2 will no t be dri-venr the rotor-.33 will bejdriven fromtthe housin causev operation. of the compressor. Z ior livery of air -.to-the;.tank;28 .i During he o of'the vehicle Ifl-thehbusingQEQLo th 4 2! and the characteristicslof gthdfctoupli hgtare such that the amount of slippage which occurs :he-

tween fthehousing and rotor ,wi-li --r.es ,ult ingthe compressor .2 2 always -being driven ahasubstantially. constant :speed for :all operating i speeds oi the driving motor I8 above ;a;pred

speeds, of (the 7 vehicle motor within the usual driving speeds of ,theNehicIea W ich ordinar ilyflrangeefrom anlidlin peedtoit 7 vehicle speedfon .theeoraer sof, ninetygor; one. lig dred milesiperrhourj When the pressure of the-Hair in thessto jaee cause an automaticppening[,oiwh .co v the switch-A9; thereby de-energizing ,thesmag etic coupling and permitting the air'coinpressorgto .come to a stop. ,When: the .,pressure .in the tank drops .,to.,a predetermined ,vlaiuegthe contaets ,,of

the switch-Adana reclosed toagaihlenetgizelthe magnetic coupling and cause the compressor to be idriven fromthe.vehiclelmotor1,8.

Although the fore oin des ription. reiers pan ticularlyr to L 'an air l, compressor, it" ,Wll, stood that 'thepresent inventioncam indriving the compress r o arr fri ere im paratus orithelike when suclrapparatusis emn s ei ,i :nrovid 'withtan ienitibncir ui an .a power takeeofi,tconiprisingva compressor adaptiedito deliver aseouslmedium nde pressure-an ve e9 romagneti icoupline c nne tin said e um- -l e ee i iih e rp w i e an b in lb er a'ble .with .lcontinuous slippage ,while energized, l a circuit .for ener izing saidicoimlin ;a--.sWT tch,d Alice controlling; said ,circuit and adapted to .be tuated nau ondaticallyzin response .to variations in the pressureroirsaiq .m d ummn th elivery slides of the compressor, and a a, second switch demise controlling ai s ir 'u an .4 serving also as vthe ignition.switch for szrideneine.

'2- agon pressonsrstem.iorametorvehi lehav insacvari h eis eed' n ernal rombustion-drivin noysze .Ltakefoil, comprisinea t nk, a omnr ss r adapted to deliver gaseous medium nnderipres sure to "said "tank, ,an electroma netic; couplin 'oqonnecting saidcprnpressor with saidjpmver take- .Qfi, nidibfii ig operable withr .contrnugus,v .while energized,,anircuitiorener izi pling, a switch device controlling,

m us t fliuminsa d -t itroilines id clrcu i h witch ,fQr-L said en ine.

.lrow an v REFERENCES 61mm riollowinerrefereneesga e gQfJjggQpd ih, the

file nflthis na'tent;

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